62 CIRCULAR 3 3 3, U.S. DEPARTMENT OF AGRICULTURE 



Intervals between repeat photographs may be lengthened. Corner 

 markers that fall over may not need to be replaced. Subplots may 

 be forgotten. Records may go uncompiled, if they are properly 

 preserved. With such handling many plots, abandonment of which 

 is considered, can be continued, possibly to surprise the investigator 

 in later years with their value. 



LITERATURE CITED 



(1) Allen, F. E., and Wishart, J. 



1930. A METHOD OF ESTIMATING THE YIELD OF A MISSING PLOT IN FIELD 



experimental work. Jour. Agr. Sci. [England] 20: 398-406. 



(2) American Joint Committee ox Horticultural Nomenclature. 



1923. standardized plant names. Prepared by F. L. Olmsted, F. V. 



Coville, and H. P. Kelsey. 546 pp. Salem, Mass. 



(3) Amiln, J. A. 



1925. ltlj.enstrom's dendrometer. Pulp and Paper Mag. 22 : 835-836. 



(4) Baldwin, H. I. 



1927. A USEFUL, QUADRAT TAKER AND REPRODUCTION COUNTER. Ecology 8 : 



385-387, illus. 



(5) Barrett, L. I. 



1929. ACCURACY OF FOREST SERVICE STANDARD HYPSOMETER. JOUl\ For- 

 estry 27: 587-588. 



(6) and Righter, F. I. 



1929. working plan for experimental thinnings in shortleaf and 

 loblolly pines. Jour. Forestry 27 : 782-803, illus. 



(7) Bates, C. G., and Zon, B. 



1922. RESEARCH METHODS IN THE STUDY OF FOREST ENVIRONMENT. U.S. 



Dept. Agr. Bull. 1059, 209 pp.. illus. 



(8) Bauer, H. A. 



1924. studying growth with an increment borer. Jour. Forestry 22 : 



298-301. 



(9) Behre, C. E. 



1926. COMPARISON OF DIAMETER TAPE AND CALIPER MEASUREMENTS IN 



second-growth spruce. Jour. Forestry 24: 178-182. 



(10) Berg, B. 



1929. AN IMPROVED METHOD FOR NUMBERING TREES ON PERMANENT SAM- 



PLE plots. Jour. Forestry 27: 750-751. 



(11) Bouyoucos, G. J. 



1930. A COMPARISON OF THE HYDROMETER METHOD AND THE PIPETTE 



METHOD FOR MAKING MECHANICAL ANALYSIS OF SOILS. WITH 



new directions. Jour. Amer. Soc. Agron. 23 : 747-751. 



(12) Bowley, A. L. 



1920. elements of statistics. Ed. 4, 459 pp., illus. London. 



(13) Bruce, D. 



1925. some possible errors in the use of curves. Jour. Agr. Research 



31: 923-928, illus. 



(14) and Reineke, L. H. 



1931. CORRELATION ALINEMENT CHARTS IN FOREST RESEARCH : A METHOD 



OF SOLVING PROBLEMS IN CURVILINEAR MULTIPLE CORRELATION. 



U.S. Dept. Agr. Tech. Bull. 210, 88 pp., illus. 



(15) Clements. F. E. 



1905. research methods in ecology. 334 pp., illus. Lincoln, Xebr. 



(16) and Goldsmith, G. W. 



1924. THE PHYTOMETER METHOD IN ECOLOGY ; THE PLANT AND COMMU- 

 NITY as instruments. 106 pp., illus. Washington, D.C. 

 (Carnegie Inst. Wash. Pub. 356.) 



(17) Davis, R. O. E., and Bennett, H. H. 



1927. GROUPING OF SOILS ON THE BASIS OF MECHANICAL ANALYSIS. U.S. 



Dept. Agr. Circ 419, 15 pp., illus. 



(18) Detwiler, S. B. 



1915. SAVING LABOR IN MEASURING HEIGHTS ; A NEW PRINCIPLE APPLIED TO 



the hypsometer. Forestry Quart. 13 : 442-444, illus. 



